a bunch of stuff mostly

parser/src/sym.rs

@@ -0,0 +1,39 @@
+use std::{cell::RefCell, fmt::Debug, marker::PhantomData};
+
+use dbg_pls::DebugPls;
+use lasso::Spur;
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Symbol {
+    spur: Spur,
+    not_send: PhantomData<*const ()>,
+}
+
+thread_local! {
+    static INTERNER: RefCell<lasso::Rodeo> = RefCell::new(lasso::Rodeo::new());
+}
+
+impl Symbol {
+    pub fn intern(s: &str) -> Self {
+        INTERNER.with(|i| Symbol {
+            spur: i.borrow_mut().get_or_intern(s),
+            not_send: PhantomData,
+        })
+    }
+
+    pub fn as_str<R>(&self, f: impl FnOnce(&str) -> R) -> R {
+        INTERNER.with(|i| f(i.borrow_mut().resolve(&self.spur)))
+    }
+}
+
+impl Debug for Symbol {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        INTERNER.with(|i| f.write_str(i.borrow_mut().resolve(&self.spur)))
+    }
+}
+
+impl DebugPls for Symbol {
+    fn fmt(&self, f: dbg_pls::Formatter<'_>) {
+        self.as_str(|s| f.debug_ident(s))
+    }
+}